Opioid overdose deaths can occur in patients with naltrexone implants

Gary K Hulse and Robert J Tait
Med J Aust 2007; 187 (1): 54. || doi: 10.5694/j.1326-5377.2007.tb01120.x
Published online: 2 July 2007

To the Editor: Gibson et al provide us with five cases of fatal drug overdose in an article titled “Opioid overdose deaths can occur in patients with naltrexone implants”.1

Three of these people did not have an active naltrexone implant — two of the deaths occurred 6 months after implant insertion (which is the outer limit of the longest duration implant available), and the implant had been removed from the third person.

This leaves only two cases.

In one of these, the cause of death was combined non-opioid drug toxicity, including amphetamine and a cocktail of other drugs, where opioids were not present. Obviously, naltrexone, an opioid antagonist, will not protect against non-opioid drug overdose.

Clearly these four cases should never have been included under the title “Opioid overdose deaths can occur in patients with naltrexone implants” (our italics).

That leaves a single fatal opioid overdose in a patient who had an active implant, and in which the cause of death was acute narcotism, where the individual had injected heroin. Here at last is a case study that should be included, and the authors note that the effects of naltrexone can be overcome, and alert us to the danger of using excess heroin to overcome naltrexone blockade.

However, this information is less than new. MIMS annual notes under “Attempts to overcome [naltrexone] blockade”:

It is also surprising that no denominator is attempted on the number of patients who may have received treatment by implanted naltrexone between 2000 and 2004. This information is available through the Therapeutic Goods Administration, and would have given the reader a clearer ability to evaluate the significance of this single case study. For example, one of the articles they cite reports one fatality in nearly 600 person-years of follow-up,3 giving a very different impression of risk compared with the article by Gibson and colleagues.

  • Gary K Hulse
  • Robert J Tait

  • University of Western Australia, Perth, WA.


  • 1. Gibson AE, Degenhardt LJ, Hall WD. Opioid overdose deaths can occur in patients with naltrexone implants. Med J Aust 2007; 186: 152-153. <MJA full text>
  • 2. MIMS Australia. MIMS annual. Sydney: CMPMedica Australia Pty Ltd, 2005.
  • 3. Hulse GK, Tait RJ, Comer SD, et al. Reducing hospital presentations for opioid overdose in patients treated with sustained release naltrexone implants. Drug Alcohol Depend 2005; 79: 351-357.


remove_circle_outline Delete Author
add_circle_outline Add Author

Do you have any competing interests to declare? *

I/we agree to assign copyright to the Medical Journal of Australia and agree to the Conditions of publication *
I/we agree to the Terms of use of the Medical Journal of Australia *
Email me when people comment on this article

Online responses are no longer available. Please refer to our instructions for authors page for more information.